Abnormalities in renal function have been reported in patients with liver disorders. Ligation or division of the bile ducts in animals is also associated with alterations in renal function. The proposed research will explore and characterize renal function in animals with bile duct ligation and in patients with obstruction of the biliary tract. Also, the research is directed toward the evaluation of some of the mechanisms underlying the abnormalities in renal function that develop after obstruction of the biliary tract. Specifically, our overall goals are to: 1. Evaluate the possible mechanisms underlying the defect in the concentrating ability after BDL. 2. Examine the role of ADH in the impaired excretion of water after BDL. 3. Investigate some of the possible mechanisms underlying the altered renal handling of sodium after BDL. 4. Study renal function in patients with obstruction of the biliary tract. 5. Investigate with electron microscopy the histological lesions in the liver after BDL and any possible structural lesion in the kidney of animals with BDL or patients with obstruction of biliary tract.